Hair is generated with skin and the hair growth cycle consists of anagen (3-5 years), catagen (1-2 months) and telogen (3-5 months). During the anagen phase, the dermis and the hypodermis are developed. Hair follicles grow in the papillary dermis of the dermis. During the catagen phase, the hair follicles come closer to the epidermis as the thickness of the dermis decreases. Dermal papilla fall off from the hair follicles and a new hair growth cycle begins.
Hair loss can be classified into telogen effluvium and anagen effluvium according to the stage of hair shedding. Telogen effluvium may be caused by the male hormone androgen, childbirth or endocrine disease. Anagen effluvium includes alopecia greata, cicatricial greata and hair loss caused by tinea capitis. Also, focal infection, endocrine disorder, genetic factors, autoimmunity, etc. are known to cause loss of hair.
A variety of signal transduction factors induce hair loss during the hair growth cycle. Growth factors such as Insulin-like growth factor 1 (IGF-1), epidermal growing factor (EGF), fibroblast growth factor (FGF), etc. promote hair growth and prevent death of hair cells, whereas Interleukin-1 (IL-1) and tumor necrosis factor (TNF) cause hair loss by inducing death of hair cells and transforming growth factor-β1 (TGF-β1) inhibits hair growth. Among the male hormones, androgen is known to reduce the hair growth and cause degeneration of hair.
Currently, representative treatments for hair loss include Propecia and minoxidil approved by the USFDA. Although these drugs show obvious clinical effects, they have side effects such as sexual dysfunction and skin irritation and are unavailable or limited for use in women. Recently, natural products which are safe can be used regardless of sex and have been actively explored.
Korean Patent No. 10-0581316 discloses a composition for inhibiting hair kiss and enhancing hair growth, which comprises a herbal extract mixture of Leonurus sibiricus, spikenard, mother chrysanthemum, peach kernel, cornus fruit, cuscuta semen, Schisandra chinensis, atractylodes rhizome, pine needle and Angelica gigas. Korean Patent No. 10-0609210 discloses a shampoo composition for inhibiting hair loss, which comprises ethanol extracts of Angelica gigas root and burdock root wherein β-sitosterol included in the Angelica gigas root suppresses 5α-reductase and inulin included in the burdock root improves blood circulation. Although they show hair loss inhibiting effect clinically, their mechanism action is not clearly understood. (see Korean Patent No. 10-0581316 and Korean Patent No. 10-0609210)